This also depends on a game, some games (Fallout 4 ) may have broken input mechanics but in most this issue can be fixed by increasing sensitivity or acceleration. Please attach log and tell us which game you are trying to play.

I think this is the limit of dualshock controller (or any controllers). Do remember that you're emulating a gamepad so ps4 won't accept any faster moves than what a normal analog does.
So my advice is don't flick your mouse.